Sudden Commencements and Impulses in Kodaikanal magnetograms -their hourly frequency

The diurnal variation in the frequencies of sudden commencements (SCs) and sudden impulses (SIs) at Kodaikanal (10.2°N, 77.5°E) is analysed from the data for the period 1949-1957.The hourly frequency curve of SCs and SIs (combined) has little resemblance to the curve obtained by Newton from his analysis of Greenwich-Abinger record. The results of harmonic analysis show a nearly semi-diurnal trend the distribution of storm sudden commencements (SSCs); this, however, is small. The hourly frequencies of SIS show s significant diurnal variation with an afternoon maximum and a forenoon maximum and a secondary minimum around 18h local time and a secondary maximum around 08h. These results are also compared with those obtained by Ferraro Parkinson and Unthank.

Interaction between air filled hollow particles and surface in water

<p>A thorough knowledge of the interaction energy between a hollow particle (HP) and a surface or between two HPs is critical to the optimization of HP-based products and assessing the environmental risks of HPs and HP-associated pollutants. The van der Waals (vdW) energy between a HP and a surface is often calculated by subtracting the vdW energies of the inner and outer HP geometries. In this study, we show that this subtraction method is only valid when the interior and exterior fluids are the same, for example, for water-filled HPs (WHPs) dispersed in an aqueous solution. Expressions were developed to calculate the vdW energies for HPs whose interiors were filled with air (AHPs). The vdW energies were then calculated between a planar surface and a spherical or cylindrical WHP and AHP, and between WHPs or AHPs. The vdW attraction between a surface and a WHP was decreased at large separation distances compared to solid particles, and this reduced the depth of the secondary minimum. In contrast, the vdW attraction for AHPs and a surface was significantly reduced at all separation distances, and even became repulsive for thin shells, and this inhibited both primary and secondary minimum interactions. The vdW attraction between WHPs decreased with increasing shell thicknesses, and this reduced aggregation in both primary and secondary minima. In contrast, aggregation of AHPs was increased in both minima with decreasing shell thicknesses because of an increase in vdW attraction. Our theoretical calculations show the evolution of vdW and total interaction energies for HPs with different interior fluids and shell thicknesses. These results help explain various experimental observations such as inhibited attachment and favorable aggregation for AHPs (e.g., carbon nanotubes) and favorable bubble coalescence.</p>

Earth's core magnetic field model Mag.num and the IGRF 13 candidate

<p>The Earth's core magnetic field model Mag.num was the parent model for the GFZ IGRF 13 candidate submission. The model is based on geomagnetic ground observatory and Swarm satellite observations. Epochs 2020.0 and beyond were not covered by the data available at the time of submission and our results were based on predictions. In this study, we investigate the effect of the more recent available data on our results of the 2020.0 epoch and the predicted secular variation by generating an updated Mag.num version. We especially focus on the spatial and temporal patterns of the local geomagnetic field minimum of the South Atlantic Anomaly (SAA). Recently, global geomagnetic field models have shown that an additional, although shallow, secondary minimum at Earth's surface has developed since around 2005. The location and significance of the secondary minimum and of the saddle point between the two minima are assessed also in view of the respective differences among the candidate models.</p>

COLLECTIVE POTENTIAL FOR HEAVY ION NUCLEAR REACTIONS

It is shown that the nuclear charge polarisation during heavy ion nuclear reactions enhances the secondary maximum of the collective energy surface and produces a secondary minimum in the deformation energy near R ~ Rmin + 2fm. The potential energy and mass formulas are given as a function of A and Z. It has been shown that charge polarisation without shape deformation and indeed of the prolate type does not produce any secondary minimum. It is also seen that the relativity effect consists in shifting the secondary minimum towards higher rest excentricities. For deformation of the oblate type the collective potential has a similar form like that in the spherical case. Entry and exit channel collective potentials are also given for the case of strong nucléon transfer. The mass for the two-body interacting system has been calculated and for large distances it tends to the corresponding reduced mass. The present theory is based on a particular form of the single particle potential following from the scalar π-meson classical field theory.

Varijabilnost padalina u Hvaru i Crikvenici

The study analyses the precipitation variability in Hvar and Crikvenica in the period from 1931 to 1990. These stations have a maritime type of the annual course of precipitation. The minimum value of the precipitation variability in Hvar is in autumn, in November, while the secondary minimum of the variability is in spring, in April. The primary maximum of variability is in summer, most often in July, while the secondary maximum is in March. In Crikvenica the minimum values of the precipitation variability in April and November are even, and the same is true for the maximum values of the variability in September and March. The value of the annual precipitation variability is higher in Crikvenica than in Hvar although Crikvenica has higher amount of precipitation. The location of the stations included in this research is relevant. In Crikvenica the variability is higher in autumn and winter. Monthly values of the mean relative variability coincide in the cold part of the year when the variability is only slightly higher in Crikvenica, while in the warm part of the year, with the exception of September, the variability in Hvar is significantly higher.

IO Com: Is it a Non-secondary Minimum Star?

Four-color photometry of IO Com, a detached eclipsing binary with a long period (~53 d), was accomplished in 2004–2008. The absolute astrophysical and orbital parameters of the system were determined by the analysis of the light and radial velocity curves. No secondary minima in the light curves were detected. It was revealed that IO Com is the system with a highly eccentric orbit consisting of the components of mid-F spectral types. The calculated masses and radii of the primary and secondary components are: 1.32

Symbiotic Nova PU Vul - 33 Years of Observations

We present UBVRI light curves of the symbiotic nova PU Vul after its outburst in 1978. Three observed eclipses of the hot component by the cool one were used to determine the ephemeris of the binary system as JD (Min I) = 2444550(15) + 4897(10) × E days. the 194-day shift of the secondary minimum from its expected positions in 2001 suggests the eccentricity of the binary orbit. Period analysis of the VRI photometry improved the pulsation period of the cool AGB variable in the system to P = 217.7 days. Pulsation of the cool component is detected only in the phases around the primary minimum, when the visible hemisphere of the AGB star is not influenced by the interaction with the hot component.